Question $17($Mandatory$)(10$ points$)$

Packages arrive at a facility at a rate of $30$ per hour and are processed continuously at a rate of $25$ per hour. The facility is open from $8$ a$.$m$.$ to $4$ p$.$m$.$ How long does the last package $($arriving at $4$pm$)$ wait before it is processed?

Question $17$ options:

$1\mathrm{.}33$ hours

$1\mathrm{.}60$ hours

$1\mathrm{.}20$ hours

$1\mathrm{.}75$ hours